1. Field of the Invention
The invention relates to a circuit board, and more particularly to an easy to assemble circuit board.
2. Description of the Related Art
FIG. 1a shows a conventional circuit board 1 comprising a substrate 10, a plurality of through holes 11, a plurality of fixing elements 20 and a plurality of annular conductive pads 21. FIG. 1b is an enlarged view of portion A in FIG. 1a, wherein a protection layer 13 and a conductive layer 14 are formed on the substrate 10. The protection layer 13 comprises hollow portions 12 surrounding the through hole 11. The conductive layer 14 is exposed in the hollow portions 12. When the fixing element 20 is fixed in the through hole 11, the annular conductive pad 21 is sandwiched between the fixing element 20 and the substrate 10. The annular conductive pad 21 contacts the conductive layer 14 exposed in the hollow portions 12 to electrically connect the conductive layer 14 and the fixing element 20.
Conventionally, the annular conductive pads 21 are utilized for electrically connecting the conductive layer 14 and the fixing elements 20, which increase costs. Additionally, during assembly, the annular conductive pads 21 are easily displaced or detached, which increase difficulty of circuit board assembly.